Sheared Flywheel Key / Posssible Timing Issue

[boatmon345]

OK guys don't laugh but the other night I mistakenly sheared the flywheel key because I forgot to torque the flywheel nut.<br /><br />My salvage supplier gave me another key, which has a slightly different shape. I installed the flywheel, but noticed some rotary play - about 1/2 of a geartooth (maybe a degree??!). I then torqued the nut.<br /><br />Is 1/2 of a geartooth significant with regards to timing? Eng seemed to run find after this. Do I need to check TDC on one of the pistons to confirm proper setting of the flywheel, or not necessary?

 

[Silvertip]

Re: Sheared Flywheel Key / Posssible Timing Issue

What you really need to do is install the correct key. Since the key locates the flywheel in relation to the crankshaft, you have no idea how much that relationship is off so how would you know how far the timing is off? The only way to determine that would be to use a piston stop, find TDC, and re-index the flywheel. You would then know how far off the timing marks are and compensate accordingly. All of this for the cost of the correct key is not worth the effort.

 

[boatmon345]

Re: Sheared Flywheel Key / Posssible Timing Issue

The width of the key is the same. Just the length seems a bit shorter.<br /><br />I guess what I am asking is does anyone know if they have slight rotary play once they have placed the flywheel on the crankshaft, but before tightening the nut. I have 1/2 gear tooth of play in the flywheel, while crank is stationary. So I could be off timeing by up to whatever degrees (or fraction of a degree) that 1/2 gear-tooth translates to.

 

[Silvertip]

Re: Sheared Flywheel Key / Posssible Timing Issue

Ahhhhh - now its perfectly clear! Sounds like its still a fairly sloppy fit and I suspect it could affect timing by a couple of degrees. Probably not a problem at idle and lower speeds but too much timing advance at wide open throttle can make holes in the pistons. Since you are dealing with a tapered shaft, the length of the key may have a bearing on that fit.